Simulating river flow velocity on global scale

Flow velocity in rivers has a major impact on residence time of water and thus on high and low water as well as on water quality. For global scale hydrological modeling only very limited information is available for simulating flow velocity. Based on the Manning-Strickler equation, a simple algorithm to model temporally and spatially variable flow velocity was developed with the objective of improving flow routing in the global hydrological model of Water- GAP. An extensive data set of flow velocity measurements in US rivers was used to test and to validate the algorithm before integrating it into WaterGAP. In this test, flow velocity was calculated based on measured discharge and compared to measured velocity. Results show that flow velocity can be modeled satisfactorily at selected river cross sections. It turned out that it is quite sensitive to river roughness, and the results can be optimized by tuning this parameter. After the validation of the approach, the tested flow velocity algorithm has been implemented into the WaterGAP model. A final validation of its effects on the model results is currently performed

Knowledge management system on flow and water quality modeling

Author name used in this publication: K. W. Chau2001-2002 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Comparative Analysis of Daily Flow Pattern Hydrographs Used to Disaggregate Monthly Naturalized Flows to Daily

Observed and synthesized sequences of stream flow data are explored from the perspective of improving capabilities for disaggregating monthly naturalized flow volumes, representing natural undeveloped conditions, to daily volumes. The research investigates 1) characteristics of river flows and impacts of water resources development on flows, 2) capabilities for disaggregating monthly naturalized flows to daily, and 3) the sensitivity of water availability modeling results to the daily flow pattern hydrographs adopted in monthly-to-daily naturalized flow disaggregation. The Texas Commission on Environmental Quality (TCEQ) Water Availability Modeling (WAM) System consists of the Water Rights Analyses Package (WRAP) and input datasets for all the river basins of Texas. TCEQ sponsored research at Texas A&M University over the past several years has included development of a daily version of the monthly WRAP/WAM modeling system. The thesis research focuses on improving capabilities for developing daily pattern hydrographs for use in disaggregating monthly WAM naturalized flow sequences to daily within the daily WRAP modeling system. Comparative statistical analyses are performed for observed and synthesized river flows at numerous gage sites in the Brazos, Trinity, Neches, and Sabine River Basins. The datasets of monthly and daily flows investigated in the thesis include observed flows at U.S. Geological Survey (USGS) gages, TCEQ WAM System naturalized flows, unregulated flows from a U.S. Army Corps of Engineers (USACE) reservoir operations modeling system, and flows generated with the Soil and Water Assessment Tool (SWAT) and Hydrologic and Water Quality System (HAWQS) watershed rainfall-runoff modeling systems. Daily WRAP simulations of the four case study river basins for a 1940-2015 hydrologic period-of-analysis are performed with alternative flow disaggregation schemes. The USACE Hydrologic Engineering Center (HEC) Data Storage System (DSS) and HEC-DSSVue are employed in the compilation and comparative analyses of datasets. Stream flow throughout Texas is extremely variable temporally with the extremes of floods and droughts as well as seasonal and continuous variability. The impacts of water resources development on river flows vary greatly between different locations. Impacts of upstream development are very different across the range of low to median to high flows. The HEC-DSSVue based approach for compiling, analyzing, comparing, selecting, and combining datasets significantly enhances the WRAP/WAM modeling system

Upper Spokane River Model: Boundary Conditions and Model Setup, 1991 and 2000

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to: • Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam • Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics) A hydrodynamic and water quality model, CE-QUAL-W2 Version 3 (Wells, 1997), is being applied to model the Spokane River system. CE-QUAL-W2 is a two dimensional (longitudinal-vertical), laterally averaged, hydrodynamic and water quality model that has been under development by the Corps of Engineers Waterways Experiments Station (Cole and Wells, 2000). In order to model the system, the following data were required: • Spokane River flow, water level and water quality data at the upstream system boundary (the State of Idaho boundary) • Tributary inflows and water quality • Meteorological conditions • Bathymetry of the Spokane River, the dam pools along the river, and Long Lake Reservoir • Point source (wastewater treatment plants, WWTPs) inflows and water quality characteristics Data have been primarily collected from 1991 to 1992 and again during 2000. This report summarizes the data used in the modeling effort

Water resources planning for rivers draining into Mobile Bay. Part 2: Non-conservative species transport models

Total coliform group bacteria were selected to expand the mathematical modeling capabilities of the hydrodynamic and salinity models to understand their relationship to commercial fishing ventures within bay waters and to gain a clear insight into the effect that rivers draining into the bay have on water quality conditions. Parametric observations revealed that temperature factors and river flow rate have a pronounced effect on the concentration profiles, while wind conditions showed only slight effects. An examination of coliform group loading concentrations at constant river flow rates and temperature shows these loading changes have an appreciable influence on total coliform distribution within Mobile Bay

Groundwater Flow andWater Quality – A Flowpath Study in the SeminoleWell Field, Cedar Rapids, Iowa

In Iowa, alluvial aquifers near major rivers are a source of water for many communities. The City of Cedar Rapids withdraws water from wells completed in the Cedar River alluvium, a shallow alluvial aquifer adjacent to the Cedar River. The City of Cedar Rapids is located within Linn County in east-central Iowa, and water for the City is supplied by four well fields (East, Northwest, Seminole, and West well fields) along the Cedar River. The City has a population of about 121,000, and several large industries are major water users. Currently, per capita water usage in the City is nearly three times the national average. The City is committed to providing both a high quality and quantity of water to its customers. The USGS and Cedar Rapids Water Department have been working together in an ongoing research program to better understand water quality and flow in the Cedar River and alluvial well fields. Work has been done on both a basin and well-field approach and has involved dye tracing/time-of-travel studies on the Cedar River, water-quality sampling, geochemical modeling, and groundwater-flow modeling

Selection and calibration of numerical modeling in flow and water quality

Volume 9, Number 3 / January, 2005Author name used in this publication: K. W. Chau2004-2005 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Water Quality Modeling: A Comparison of Transport Oriented and Biochemistry Oriented Approaches

The author was a rapporteur for the session on "Flow Related Transport Phenomena: Water Quality" at the International Conference on Numerical Modelling of River, Channel and Overland Flow for Water Resources and Environmental Applications, organized by IAHR, WMO, IIASA, and the Czechoslovakian Committee of IAHR, and held in Bratislava, Czechoslovakia, May 4-8, 1981. The request to the rapporteur was to give an overview of the related subject. This formed the first part of the original report and is published here since it considers some typical features and an apparent gap in water quality modeling, and is therefore of more general interest. The papers reviewed are listed in the Appendix

Use of habitat suitability modeling in the integrated urban water system modeling of the Drava River (Varazdin, Croatia)

The development of practical tools for providing accurate ecological assessment of rivers and species conditions is necessary to preserve habitats and species, stop degradation and restore water quality. An understanding of the causal mechanisms and processes that affect the ecological water quality and shape macroinvertebrate communities at a local scale has important implications for conservation management and river restoration. This study used the integration of wastewater treatment, river water quality and ecological assessment models to study the effect of upgrading a wastewater treatment plant (WWTP) and their ecological effects for the receiving river. The WWTP and the water quality and quantity of the Drava river in Croatia were modelled in the software WEST. For the ecological modeling, the approach followed was to build habitat suitability and ecological assessment models based on classification trees. This technique allows predicting the biological water quality in terms of the occurrence of macroinvertebrates and the river status according to ecological water quality indices. The ecological models developed were satisfactory, and showed a good predictive performance and good discrimination capacity. Using the integrated ecological model for the Drava river, three scenarios were run and evaluated. The scenario assessment showed that it is necessary an integrated approach for the water management of the Drava river, which considers an upgrading of the WWTP with Nitrogen and Phosphorous removal and the treatment of other diffuse pollution and point sources (including the overflow of the WWTP). Additionally, if an increase in the minimum instream flow after the dams is considered, a higher dilution capacity and a higher self-cleaning capability could be obtained. The results proved that integrated models like the one presented here have an added value for decision support in water management. This kind of integrated approach is useful to get insight in aquatic ecosystems, for assessing investments in sanitation infrastructure of urban wastewater systems considering both, the fulfilling of legal physical chemical emission limits and the ecological state of the receiving waters

Applications of Expanded WRAP Modeling Capabilities to the Brazos WAM

The Water Rights Analysis Package (WRAP) is routinely applied in the Texas Commission on Environmental Quality (TCEQ) Water Availability Modeling (WAM) System. However, the Brazos River Basin studies documented by this report represent inaugural applications of the following new WRAP modeling capabilities: (1) conditional reliability modeling to determine short-term storage and flow frequencies and supply reliabilities conditioned on preceding reservoir storage contents; (2) capabilities added to allow simulations to be performed with daily time steps; and (3) simulation of reservoir operations for flood control. The Brazos WAM studies presented in this report provide a data and experience base for evaluating, demonstrating, and developing guidance for applying the new WRAP modeling capabilities. The studies also provide a better understanding of water management in the Brazos River Basin